Molecular Structure Flashcards
What is the empirical formula?
The simplest formula for an organic compound - It shows all the elements present in a compound in the simplest ratio. For example, the empirical formula for benzene (C6H6) is just CH.
What is the molecular formula?
The molecular formula shows the actual number of atoms of each element in a compound.
How can you work out the molecular formula from an empirical formula?
If you know the empirical formula and the relative molecular mass of the compound, the molecular formula can be worked out;
For example, for a compound with the empirical formula CH20 and a relative molecular mass of 60 you would first work out the relative empirical mass (12+2+16=30). As the empirical mass is half of the molecular mass, the molecilar formula must be twice the empirical formula: C2H402.
What is the structural formula?
The structural formula shows exactly how the atoms are bonded together and can either be:
- Full structural formula: All bond between the atoms are displayed.
- Abbreviates structural formula: The structure is condensed, either just the branches or the whole thing.
What is the skeletal structural formula?
The skeletal structural formula uses lines to represent the carbon-carbon backbone. Each line has a carbon at each end of it unless there is another atom attached. The skeletal formula doesn’t show hydrogen atoms that are attached to carbons.
What is wedged line notation?
Wedged line notation is a simple way of showing organic molecules with a 3D shape. The plain lines represent bonds that lie in the plane of the paper. The full wedge represents a bond coming out of the paper and the hashed wedge represents a bond behind the paper.
